Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
195 words
In a gas sensor having a tubular metal casing, a rod-shaped holder of a ceramic material formed with a plurality of axial through-holes and tightly fitted in the tubular casing, a gas sensing element which operates on an electrochemical principle and which is fixed to a forward end of the rod-shaped holder, a plurality of lead wires which are attached to the gas sensing element and respectively passed through the through-holes in the rod-shaped holder, and a heat-resistant sealant filled into the through-holes in the holder, the improvement comprising a rod-shaped plug of a ceramic material, said plug being pre-formed with a plurality of axial through-holes and tightly fitted in an end portion of said tubular casing so as to leave a space between the rear end of said holder and the forward end of said plug, said lead wires being respectively passed through said through-holes in said plug across said space, and a hermetic sealant which fills said space between said holder and said plug and said through-holes in said plug, said hermetic sealant comprises a lead glass which is solidified from a molten state within said space and said through-holes in said plug.
Claim 2
Dependent Claim
195 words
In a gas sensor having a tubular metal casing, a rod-shaped holder of a ceramic material formed with a plurality of axial through-holes and tightly fitted in the tubular casing, a gas sensing element which operates on an electrochemical principle and which is fixed to a forward end of the rod-shaped holder, a plurality of lead wires which are attached to the gas sensing element and respectively passed through the through-holes in the rod-shaped holder, and a heat-resistant sealant filled into the through-holes in the holder, the improvement comprising a rod-shaped plug of a ceramic material, said plug being pre-formed with a plurality of axial through-holes and tightly fitted in an end portion of said tubular casing so as to leave a space between the rear end of said holder and the forward end of said plug, said lead wires being respectively passed through said through-holes in said plug across said space, and a hermetic sealant which fills said space between said holder and said plug and said through-holes in said plug, said hermetic sealant comprises a lead glass which is solidified from a molten state within said space and said through-holes in said plug.
Claim 3
Dependent Claim
47 words
A gas sensor according to claim 1, wherein said lead glass is selected from the group consisting of PbO-B 2 O 3 base lead glass, PbO-SiO 2 base lead glass, PbO-ZnO-B 2 O 3 base lead glass and PbO-SiO 2 -B 2 O 3 base lead glass.
Claim 4
Dependent Claim
24 words
A gas sensor according to claim 1, wherein said through-holes in said plug are larger in cross-sectional area than said through-holes in said holder.
Claim 5
Dependent Claim
20 words
A gas sensor according to claim 3, wherein said holder and said plug are made of the same ceramic material.
Claim 6
Dependent Claim
25 words
A gas sensor according to claim 1, wherein said hermetic sealant intrudes into a rear end portion of each of said through-holes in said holder.
Claim 7
Dependent Claim
35 words
A gas sensor according to claim 1, wherein each of said through-holes in said holder has a cross-sectionally enlarged portion as a rear end portion thereof, said enlarged portion being filled with said hermetic sealant.
Claim 8
Dependent Claim
30 words
A gas sensor according to claim 6, wherein said through-holes in said plug are substantially similar in cross-sectional area to the cross-sectionally enlarged portions of said through-holes in said holder.
Claim 9
Dependent Claim
21 words
A gas sensor according to claim 1, wherein said heat-resistant sealant comprises a powdered ceramic material as a principal component thereof.
Claim 10
Dependent Claim
61 words
A gas sensor according to claim 1, further comprising a sleeve, a portion of which is tightly fitted around a rear end portion of said tubular casing, and a rod-shaped plug of an organic elastic material which is tightly fitted into the remaining portion of said sleeve and formed with a plurality of axial through-holes into which said lead wires extend.
Claim 11
Dependent Claim
30 words
A gas sensor according to claim 9, wherein a gap is left between the rear end of said plug of said ceramic material and said plug of said organic material.
Claim 12
Dependent Claim
17 words
A gas sensor according to claim 1, wherein said gas sensing element is an oxygen sensing element.
Claim 13
Dependent Claim
29 words
A gas sensor according to claim 11, wherein said oxygen sensing element comprises an oxygen ion conductive solid electrolyte and operates on the principle of an oxygen concentration cell.